RichEdit控件加载背景图片

unit   Unit1;

    

interface   

    

uses   

      Windows,   Messages,   SysUtils,   Variants,   Classes,   Graphics,   Controls,   Forms,   

      Dialogs,   StdCtrls,   Buttons,   ComCtrls,   ExtCtrls,   jpeg;   

    

type   

      TForm1   =   class(TForm)

      Image1: TImage;

      RichEdit1: TRichEdit;

      procedure   ClassWndProc(var Msg: TMessage);

      procedure FormCreate(Sender: TObject);

      private   

          {   Private   declarations   }

      public   

          {   Public   declarations   }

      end;  

var

Form1: TForm1;

///////////////几个重要参数///////////

wproc: pointer;

oldproc: TWndMethod;

bb: hBrush;

implementation

{$R   *.dfm}

procedure Tform1.ClassWndProc(var Msg: TMessage);

begin

if msg.Msg = WM_ERASEBKGND then

      msg.result:=1

else if (msg.Msg=CN_CTLCOLORMSGBOX) or (msg.Msg=CN_CTLCOLORSTATIC) then

begin

    bb:=null;

    msg.result := bb

end

else

    oldproc(msg)

end;

procedure TForm1.FormCreate(Sender: TObject);

begin

oldproc:=RichEdit1.WindowProc;

RichEdit1.WindowProc := form1.ClassWndProc;

SetWindowLong(RichEdit1.Handle,   GWL_EXSTYLE,   GetWindowLong(RichEdit1.Handle,GWL_EXSTYLE)   or   WS_EX_TRANSPARENT);

end;

end.

说明：

1.   使RichEdit的窗口透明.   SetWindowLong(RichEdit.Handle,   GWL_EXSTYLE,   GetWindowLong(RichEdit.Handle,GWL_EXSTYLE)   or   WS_EX_TRANSPARENT);   

    

2.   截获RichEdit的Wndproc,   处理以下消息:   

          CN_CTLCOLORMSGBOX..CN_CTLCOLORSTATIC:   返回一个NullBrush的handle   

(防止编辑状态时

清除背景).   

          WM_ERASEBKGND:   什么都不做就返回1(防止窗口在刷新时清除背景)